Shock absorbing pedestal for seats



Feb. 10, 1942- A.'M.K|MBRO SHOCK ABSORBING PEDESTAL FOR SEATS Filed oo't. 7, 1946 "IIIIIIIII'l INVENTOR ATTO R N EYS Patented Feb. 10, 1942 UNITED STATES ATENT` OFFICE 2,272,344 SHOCK ABSORBING PEDESTAL FOR SEATS Albert M. Kimbro, Houston, Tex. Application October 7, 1940, Serial No. 360,156

4 Claims.

The present invention relates to improvements in seats especially designed for motor buses and more particularly to a shock absorbing pedestal for such seats.

The primary object of the invention resides in the provision of means forming a part of a seat supporting pedestal for absorbing the shock ooca-sioned by a motor bus travelling over a rough or uneven highway,

A further object of the invention is tov provide a shock absorber of the telescoping cylinder type including the use of a multiplicity of coil springs with means being provided for varying the tension of the springs in accordance with the weight of the user of the seat.

A still further object of the invention resides in the provision of a shock absorber for the seats of buses or the like including a pair of telescoping cylinders, a piston slidably mounted in the upper cylinder and coil springs mounted in the lower and upper cylinders at o-pposite sides of the piston and separate means adapted to be operated by the user of the seat for varying the tension of certain of the springs held within the cylinders.

The invention also consists in certain other features oi construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawing and specioally pointed out in the appended claims.

In describing Iny invention in detail, reference will be had to the accompanying drawing Wherein like characters denote like or corresponding parts throughout the several views, and in which:

Figure 1 is a side elevational view of a bus seat supported upon a shock absorbing pedestal embodying the features of the present invention.

Figure 2 is a front elevational view thereof.

Figure 3 is a vertical sectional view through the pedestal with the seat removed therefrom.

Figure 4 is a front elevational view `of the pedestal with the seat removed therefrom.

Figure 5 is a horizontal sectional view taken substantially on line 5-5 of Figure 3.

Figure 6 is a top plan view of the pedestal with the seat removed therefrom.

Referring to the drawing for a more detailed description thereof, the two telescoping cylinders are designated by the numerals 8 and 9, the lower cylinder 9 having its end Ill closed and supporting therein a relatively heavy coil spring II. The lower end of the spring II is held within a groove I2 formed in the end IU, while the upper end of said spring is supported in a slot I3 formed in the lower edge of the cylinder 8. The anchoring of the ends of the spring II in the respective cylinders, prevents rotation of said cylinders, movement thereof being limited in a vertical direction. A relatively lightweight oil will be confined within the cylinder 9 and maintained at a predetermined level for lubricating the movable parts as well as to decrease the amount of air in said cylinder.

A piston I4 is slidably held within the cylinder 8 and is normally positioned adjacent the lower end of said cylinder as shown in Figure 3. A relatively large opening I5 is formed centrally of the piston I4 and communicates with an aperture I6 formed in the lower end thereof, said aperture being closed by means of a check valve I1. A second aperture IBs formed vertically of the piston I4 for connecting the upper and lower cylinders. When the two cylinders telescope, air is forced out of the lower cylinder 9 up through the aperture I6 where it is vented through the upper end oi the upper cylinder. The aperture I8 acts as a by-pass for allowing the air to return to the lower cylinder as the various parts of the shock absorber assume their balanced position as will hereinafter appear.

The upper end of the cylinder 9 contains a packing I9 of suitable lconstruction which is retained in place by means of the packing nut 20 threadedly attached to said cylinder as indicated at 2I. A spring 22 is disposed between the packing and the upper end of the nut 20 for maintaining a proper pressure on the packing thereby alleviating the possibility of the occurrence of a leakage Ias the cylinders telescope,

The lower end of the cylinder 8 is provided with a circumferentially formed groove 23 adapted to be engaged by the spring pressed dogs 24 carried by the cylinder 9 for preventing separation of the cylinder 8 from the cylinder 9 thereby limiting the upward movement of the former. The spring pressed dogs 24 are held in spaced relation on the cylinder 9 as shown in Figure 5 of the drawing, a cap nut 25 being provided for maintaining the dogs in position.

A feature of the present invention embodies the use of springs. 2B and 2l less rigid than the spring II. The spring 2l is held within the spring II and has one end resting against the bottom wall 9 and its other end in engagement with the lower end of the piston I4, while the spring 26 has one end in engagement with the upper face of the piston I4 and its other end in engagement with a cap 28 which is slidably land adjustably held in the cylinder 8. The cap 28 and as the two cylinders start back to their noris formed with vent openings 29 for allowing the escapement of air from said cylinders as the springs are compressed when absorbing a shock. The piston I4 is held in a balanced position between the springs 26 and 2l and is movable vertically by the compression and expansion of said springs.

The upper cylinder 8 has welded or otherwise secured thereto as indicated at 3l) a flange plate 3| to which the seat generally designated by the reference numeral 32 is attached. The lower cylinder 9 is likewise provided with a flange plate 33 by means of which said cylinders are attached to the floor 34 of the bus. Bolts or similar means 35 are employed for securing Asaid plate to the iioor and it will be observed that the lower end of the cylinder projects below the floor so as to permit the use of a longer spring therein having greater strength. The upper plate 3l is formed with openings 36 through whichk bolts 37 or similar means extend for attaching the seat 32 thereto n A means has also been provided for adjusting the tension of the spring 26 and 2'! to compensate for difference in the weights of passengers using the seat, said means including a horizontally disposed lever 38 having a crank section 3Q formed intermediate its ends, said lever being suitably journalled, as indicated at im, to the spring 2 since the latter spring is controlled by the action oi the piston lil. The lever 33 is held beneath the cushion of the seat 32 and has one end projecting from the front of the seat and on that end is mounted a coil spring d which is held under tension sufficient to counterbalance the force exerted on it by the spring 2B in the upper cylinder 8. As is to be understood, one end of the spring 42 is aixed to the plate 3l as indicated at 43 and the other end is suitably anchored to the lever. having serrations i5 formed on one face thereof is attached to the upper race of the plate 3l above the lever 38, the serrated portion adapted to be engaged by a pin i6 carried by the lever 38 for retaining said lever in adjusted position. When desiring to vary the tension on the springs 26 and 27, the lever SG is revolved so that the arm lll will urge the cap 23 downwardly compressing the spring 2E against the piston lll. The position oi the piston lll may vary due to its downward pressure on the spring 2l and thus both of said springs will be under additional compression. The springs will be held in the compressed position including the cap 23 when the pin .'36 engages the member ifi and all parts will be held in this position until manually moved.

When the seat is in use, the cylinder 8 will telescope within the cylinder 9 against tension of the springs l! and 2l until said springs balance the weight of the passenger. When a shock is transmitted upward by the base it is absorbed by all of the springs thus slightly depressing them from their balanced position. The sliding piston ill prevents the springs 26 and 21 from suddenly springing back to their original position, As the cylinders telescope and the springs are compressed, air is forced out of the lower cylinder 9 through the aperture I6 and out of the upper cylinder through the vents 29 A U-shaped member M mal balanced position, a partial vacuum will be formed in the lower cylinder because of the position of the check valve I'I. This vacuum will retard the upward action of the piston and will maintain some of the tension in the lower spring 2l. The upper spring 26 will lose some of its tension because of the piston being held back by the vacuum created. The aperture i8 in the piston M acts as a by-pass allowing the air to come back into the lower chamber as the springs, the piston and the cylinders resume their balanced state. With oil or similar fluid in the lower cylinder, a vacuum will be created the instant that the piston starts to return to its normal position. Thus the shock absorber in accordance with the present invention will eiece tively cushion and absorb various shocks and is prevented from a rapid return to normal position by the action of the vacuum created in the cylinder.

Also it will be understood, of course, by those skilled in the art that variations in the hereinabove described device involving the substitution of substantial equivalents for the devices described are intended to be comprehended within the spirit of the present invention and that the invention is capable or" extended application and is not confined to the exact showing of the drawing nor to the precise construction described and, therefore, such changes and modifications may be made therein as do not alTect the spirit of the present invention nor exceed the scope thereof as expressed in the appended claims.

What is claimd is.'

1. In a shock absorbing pedestal, a lower cylinder closed at the bottom end and adapted to be mounted in fixed position, an upper cylinder closed at the top and having its lower portion slidably fitted within the upper portion of the lower cylinder, a coil spring mounted in the lower cylinder and engaging the bottom edge of the upper cylinder to yieldingly support the latter, the lower portion of the said upper cylinder having an annular groove formed therein, and a plurality of spring pressed dogs mounted radially on the upper portion of the lower cylinder operative to limit the upward movement of the said upper cylinder.

2. In a shock absorbing pedestal, a lower cylinder closed at the bottom end and adapted to be mounted in xed position, an upper cylinder closed vatthe top and having its lower portion slidably tted within the upper portion of the lower cylinder, a coil spring mounted in the lower cylinder and engaging the bottom edge of the upper cylinder to yieldingly support the latter, the lower portion of the said upper cylinder having an annulargroove formed therein, a piston slidably mounted within the upper cylinder having a bore of relatively large diameter formed axially therethrough and-a bore of smaller diameter parallel with the said larger bore, a check valve `member mounted to prevent downward movement of A:fluid through the larger bore of the said piston, a Icoil spring disposed between the bottom of the piston and the closed bottom of the lower cylinder, and asecond coiled spring mounted between the top of-tlie piston and the closed top of the upper cylinder.

3. In a shock absorbing pedestal, a lower xed cylinder closed at Vthe vbottom end, an upper cylinder having its loweropen end portion slidably fitted within the upper portion of the lower cylinder, a coiled spring resting on the bottom end of the lower cylinder and engaging the bottom open end of the upper cylinder to yieldingly support the latter, a piston slidably mounted in the said upper cylinder, the said piston having an axial bore of relatively large diameter and a parallel bore of reduced diameter therethrough, a ball check Valve operative to preclude downward movement of uid through the larger bore through the said piston, an apertured cap slidably tted in the upper portion of the upper cylinder, a coil spring resting on the bottom of the lower cylinder and engaging the bottom face of the piston, an upper coil spring disposed between the top face of the piston and the axially slidable cap in the upper portion of the upper cylinder, and manually operative mechanism for axially sliding the said cap for varying the compression of the said piston contacting springs.

4. In a shock absorbing pedestal, a lower xed cylinder closed at the bottom end, an upper cylinder having its lower open end portion slidably tted within the upper portion of the lower cylinder, a coiled spring resting on the bottom end of the lower cylinder and engaging the bottom open end of the upper cylinder to yieldingly support the latter, a piston slidably mounted in the said upper cylinder, the said piston having an axial bore of relatively large diameter and a parallel bore of reduced diameter therethrough, a ball check valve operative to preclude downward movement of fluid through the larger bore through the said piston, an apertured cap slidably fitted in the upper portion of the upper cylinder, a coil spring resting on the bottom of the lower cylinder and engaging the bottom face of the piston, an upper coil spring disposed between the top face of the piston and the axially slidable cap in the upper portion of the upper cylinder, a seat supporting member mounted on the upper end of the said upper cylinder, and a lever rotatably supported on the said seat supporting member and connected with the said cap for selectively sliding the cap to vary the compression of the piston engaging springs.

ALBERT M. KIMBRO. 

